Carburetor for internal combustion engines



April 27, 1937. R. M. GROSJEAN f I 2,078,849

CARBURETOR FOR INTE RNAL COMBUSTION ENGINES Filed Sept. 22, 1934 3 Sheets-Sheet 1 Lu Lu INVENTOR.

April 27, 1937. R. M. GROSJEAN 7 GARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Sept. 22, 1934 s Sheets-Sheet 2 IN V EN TOR.

Ap 1937- R. M- GROSJEAN 2,078,849

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Sept. 22, 1934 5 Sheets-Sheet 3 IN VEN TOR.

UNITED" STATES rgre w, OFFICE GARBURETOR FOR INTERNAL COMBUSTION ENGINES Reuben M. Grosjean, Omaha, Nebr. Application September 22, 1934, Serial No. 745,135

' 10 Claims.

My invention relates to improvements in carburetors or charge forming devices which have a throttle and which'meter air and hydro-carbonfuel to internal combustion engines through "*a wide range of speeds and loads; and the Objects of my improvementare, first, to provide a practical means by which the increase and decrease in volume of 'air passing through the carburetor -automatically varies-the area of the venturi or air metering tube through the entire range of speeds and loads, making practical the metering of the air through a single opening; second, to provide a fuel metering valve to operate in conjunction with the varying venturi or air metering tube, which will accurately meter fuel throughout the required range, which will not be easily clogged with sediment, and will not wear rap-idly; third, to provide an accurate means by which the richness of the fuel'and air mixture'is increased at full, throttle V and decreased at part throttle; fourth, to provide an air cushion which will damp out flutter of moving parts iwhich wouldresult from the drop in air velocity between'the passing of adjacent cylinder charges; and fifth, to sum up an objects, to, provide in a carburetor, a

dependablecombination of mechanism which will eliminate so called, "f latf spots, and will accurately meter hydro-carbon fuel to internal combustion engines throughout .the wide range of speeds and loads as required in modern automobiles.

I I obtain these objects by mechanism illustrated in the accompanying: drawings, in which Figure 1 is aplan view and Fig. 2, an elevation,

' each of the entire carburetor e Fig. 3 is an elevation with cover plate removed.

and part of cover casting broken away to show moving parts of the carburetor; n

Fig. 4 is a cross-section of the fuel metering valve. and fixed wall of theventur'i or air metering tube at the point where fuel enters air stream;

1 Fig. '5 is a longitudinal section of the fuel metering valve;

Figs. 6, '7, and 8, are. cross-sections on line A-B, Fig. Epshowing the'fuel meteringvalve shaft or rotatable member turned to three-different valve openings;

Fig. 9. shows thespi ing-loaded rotor tercepts the air passage through the carburetor," forms piston upon which suction actsto rotate,

Fig. 10 isa vertical section showingthe fuel system of the carburetor and the air and mixture path through the carburetor;

Figs. 11 and 12 show the construction of the low speed fuel adjustment and the levers through which the fuel metering valve'is operated;

Fig. 13 is a diagrammatic view showing the two extreme and an intermediate position of the rotor,

and the relativepositions of the levers through whichthe fuelinetering valve is operated.

Similar numerals refer to similar parts throughout the several views.

The castings l5 and I6 and the throttle body I! form the fixed walls of the air passage through the carburetor, and with cover plates I8, I9, and 20, form an enclosure for the moving parts.

Rotor 2|, shown in Figs. 3, 9, and 10, is carried imum.

Referring to Fig. 3, and the diagrammatic view,

Fig. 13, all movements of said rotor are transmitted to the rotatable member of the fuel metering valves, 33, by pin 24, which is fastened tol rotor 2l and works through a slot in cover casting l6, connecting rod 25, lever 26 with trunnions at 2'! and 28 and movable fulcrum at 29, and the low speed adjustment assembly 30, 3|, 32, and 33 which assembly is rotated about the axis of 33 as one unit except when being adjusted. Said low speed adjustment assembly is shown in detail in Figs. 11 and 12. Arm 32 is clamped to the rotatable member of the fuel metering valve. Arm 30 fits over the hub of arm 32 and may be rotated on said hub by turning adjusting screw 3| which engages in nut 55.

spring 56 which engages a notch in the head of the adjusting screw. Spring 51 holds arm 30 firmly against the head of the adjusting screw, preventing backlash. Lover 26 is carried on trunnion 28 by the upper end of arm 30, and the lower 'end of lever 26 is guided by fulcrum 29 which has a transverse hole for lever 26 to slide in. Fulcrum 29, referred to in above paragraph, is pivoted on slide bar 36, which slide bar slides inguides in cover casting l6, and is connected to the throttle shaft 39 by connecting rod 3'! and lever 38. When the throttle is in idling 25 through the carburetor is increased to its max- The adjustment is retained by position, the axis of said fulcrum is approximately in line with the axis of the fuel metering valve 33. As the throttle is opened slide bar 36 is slid downward, carrying with it said fulcrum. At full throttle said bar and fulcrum are in the position as shown in full line in Fig. 3.

Fig. 13 shows three positions of rotor 2| and two extreme positions of fulcrum 29, and the relative positions of pin 24, connecting rod 25, trunnion 21, lever 26, trunnion 28, and lever 30. Two positions of lever 26, trunnion 28 and lever 30 are shown for each of the rotor positions, one for each position of fulcrum 29.

By this arrangement of levers the richness of the mixture is increased in the same proportion throughout the range of speeds by the change from part throttle to full throttle. The length of the levers may be so proportioned as to closely give the most powerful mixture at full throttle, and the most efiicient mixture at part throttle, regardless of speed the engine is running.

The air and mixture path through the carburetor and the fuel system of the carburetor are shown in Fig. 10. Fuel reservoir 52, float 53, float valve 54, fuel passages 48 and 49, fuel metering valve 33, and fuel orifice constitute the fuel system. The air enters at the top of the carburetor, passes the choke valve 5|, is mixed with fuel from orifice 50 as air passes through the narrow throat of the air metering tube and leaves the carburetor, as a mixture, through the throttle body IT.

The fuel metering valve, previously referred to, is shown at 33, Fig. 3, and in detail in Figs. 4, 5, 6, '7, and 8, and is composed of fuel metering valve shaft or rotatable member 33, and fuel metering valve body 34. Said fuel metering valve body, which I prefer to make of bronze, has a narrow transverse slit cut through one side and a relief out nearly through, thus forming a metering orifice with short sides, and sharp, square edges both at entrance and discharge. Three sides of the metering orifice are formed by the sides and one end of this slit, and the fourth side is formed by the fuel metering valve rotatable member, which has a large recess cut from one side at an end, allowing clear entrance to metering orifice regardless of amount the valve is open. The effective length of the metering ori-' fice is increased by angular movement of the fuel metering valve rotatable member in one direction, and decreased by angular movement in the other direction. Fig. 6 shows the valve in about the position it would be in at low idling sp'eed;

Figs. '7 and 8 show it, respectively, half open and full open. Fuel enters the air stream. at 50, at'

point of highest air velocity.

Rotor 2|, previously referred to, is so constructed, pivoted, and housed that an increase in suction causes said rotor to rotate in the direction which moves the cam-shaped surface on said rotor, contiguous to the air stream, in the same direction air is flowing. This is accomplished by so constructing said rotor and its housing that the preponderance of force exerted on the rotor by suction lies between the rotor pivot and the venturi. and that this preponderance is great enough to over-balance the counterforce exerted on the cam-shaped surface on said rotor in the venturi. hub of the rotor at 42 and at 43, and the space 44, between 42 and 43, is connected with the space below the rotor by the air passage 45 with opening at 46. Thus the space 41, which forms the air cushion chamber, is directly connected by Partition 4! fits up to the rotor clearance with only the space below the rotor. The pressure in said air cushion chamber does not fluctuate rapidly but is at all times tending to equalize through rotor clearance, with the mean pressure of the air below the rotor.

What I claim and desire to secure by Letters Patent of the United States is:-

1. In a carburetor, the combination of a housing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube with rectangular cross-section having fixed walls formed by said housing, and also having a moving! or varying wall for varying the width of the opening through said air metering tube, a fuel orifice in said air metering tube, a fuel reservoir, a fuel passage connecting said fuel reservoir with said fuel orifice, a fuel metering valve in said fuel passage, a rotor pivoted in said housing, a cam-shaped surface on said rotor for forming said varying wall of said air metering tube, said rotor constructed and housed in such a manner that angular movement of said rotor is effected, and the width of the opening through said air metering tube is increased by an increase in the volume of air passing through the carburetor, an air cushion chamber for said rotor formed in said housing with said rotor forming its piston, said air cushion chamber directly connected by rotor clearance with only the space between said rotor and the throttle of the carburetor, and proportioning means interconnecting said rotor and the movable member of said fuel metering valve so that the fuel metering valve is actuated by movements of the rotor.

2. In a carburetor, the combination of a housing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube with rectangular cross-section and with a varying wall for varying the width of the opening through said air metering tube, a fuel orifice in said air metering tube, a fuel reservoir, a fuel passage connecting said fuel reservoir with said fuel orifice, a fuel metering valve in said fuel passage,a spring-loaded, suction-operated rotor with part of its exterior surface formed in the shape of a cam for forming said varying wall of said air metering tube, an air cushion chamber, for said rotor, formed by said housing and said rotor for damping out flutter of said rotor, said air cushion chamber being directly connected by rotor, clearance with only the space between said rotor and the throttle of the carburetor, and proportioning means interconnecting said rotor and the movable member of said fuel metering valve so that the fuel metering valve is actuated by movements of the rotor.

3'. In a. carburetor, the combination of a housing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube with rectangular cross-section and with three fixed walls and one moving or varying wall in said mixing chamber, a fuel orifice in the form of a narrow slit across or part way across a fixed wall of said air metering tube, a fuel reservoir, a fuel passage connecting said fuel reservoir with said fuel orifice, a fuel metering valve in said fuel passage, a spring-loaded, suctionoperator rotor with part of its exterior surface formed in the shape of a cam pivoted in said mixing chamber, said housing formed to accommodate said rotor in such a manner that the cam-shaped surface on said rotor forms the varying wall of said air metering tube, said rotor and housing being constructed in such a manner movement is-insuch adirection that the part of saidrotor which is contiguous tothe air stream of said air metering tube moves in the same direction as the air stream-flowing through said ainmeteringitube, an: air cushion chamber "forsaidrotor formed 'by the walls of saidhousing and said rotor, a double air seal at thehub of: said rotor withthe space between the two parts a of saidair sealc'onnected with thespace between said rotor and the throttle of the carburetor, and

adapted .to be'subjected to the fluctuating pressure therein, and connectingimeans whereby the" movable member of said fuel metering valve is connected to, operated by, and co-operates with said rotor to hold the air. and fuel metering velocities within a practical range and to form an accurately proportioned mixture of air and liquid fuel at varied speeds and loads.

4. In a carburetor, the combination of a hous-' ing having a mixing chamber .formed therein, said mixing chamber comprising an air metering tube the fixed walls .of which-are formed'bysaid housing, a varying wall "for. varyingthe width of the opening through said airmeteringtube, a fuel orifice in said air. metering -tube,-a

fuel reservoir, a fuel passage connecting said fuel reservoir with said fuel orifice a fuelmetering valve in said fuel passage for regulating the quantity of fuelpassing to.said fuelorifice, a

suction-operated rotor with part of its exterior surface formed in the shape of a cam, said rotor housed and pivoted in said housing in such a manner that the cam-shaped surface on said rotor is contiguous to the air stream of said air metering tube and that angular movement of said rotor in onedirection increases the width of the air passage through said air metering tube and angular movement in the other direction of therotor decreases the width of the air passage through said air metering tube, an air chamber for said rotor formed by said housing and said rotor for damping out flutter of said rotor, said air chamber being directly connected by rotor clearance with only the space between said rotor and the throttle of the carburetor, and proportioning means interconnecting said rotor and the movable member of said fuel metering valve so that the fuel metering valve is actuated by angular movements of the rotor.

5. In a carburetor, the combination of a housing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube the fixed walls of which are formed by said housing, a varying wall for varying the width of the opening through said air metering tube, a fuel orifice in said air metering tube, a fuel reservoir, a fuel passage connecting said fuel reservoir with said fuel orifice, a fuel metering valve in said fuel passage, a rotor with part of its exterior surface formed in the shape of a cam, said rotor pivoted and housed in said housing in such a manner that the cam-shaped surface on said rotor forms said varying wall of said air metering tube, said rotor and housing constructed in such a manner that angular movement of said piston thereof, said air cushion chamber being directly connected by rotor clearance with only the space between said rotor and the throttle of thecarburetor, and proportioning means interconnecting said rotor and the movable member of said fuel metering valve so that the fuel metering valve is actuated by movements of the rotor.

ing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube with rectangular cross-section and with three fixed walls and one moving or varying wall in said mixing chamber, a fuel orifice in said air metering tube, a fuel reservoir, a fuel passage connecting said fuel reservoir with said fuel orifice, a fuel metering valve in said fuel passage for regulating the quantity of fuel passing to said orifice, a rotor with part of its exterior surface formed in the shape of a cam, said rotor housed and pivoted in said housingin such a manner that "the cam-shaped surface on said rotor is contiguous to the air stream of said air metering tube and that angular movement of said rotor in one direction increases the width of the air passage through said air metering tube and angular movement in the other direction of the rotor decreases the width of theair passage through said air metering tube, an air cushion chamber for said rotor formed bysaid housing and said rotor. for damping out flutter of said rotor,'said air cushion chamber being of sumcient capacity that the magnitude of the torque valve so that the fuel metering valve is actuated by movements of the rotor.

"7. In a carburetor, the combination of a housing having a mixing chamber formed therein,

said mixingchamber comprising an air metering tube with rectangular cross-section the fixed walls of which are formed by said housing, a varying or moving wall for varying the width of the opening through said air metering tube, a fuel orifice in said air metering tube, a fuel reservoir, a fuel passage connecting said fuel reservoir with said fuel orifice, a fuel metering valve in said fuel passage, said fuel metering valve composed of a stationary member and a rotatable member, a suction-operated rotor pivoted in said housing, a cam-shaped surface on said rotor forming said varying wall of said air metering tube, a partition fixed in said housing closing passage at the side of said rotor opposite to the air metering tube and up to the hub of said rotor, an air cushion chamber for said rotor formed in said housing with said rotor forming its piston, a double air seal at the hub of said rotor with the space between the two parts of said air seal subject to the fluctuating pressure of the space between said rotor and the throttle of the carburetor, and proportioning means including a connecting rod and levers, interconnecting said rotor and the movable member of said fuel metering valve so that the fuel metering valve is actuated by movements of the rotor.

8. In a carburetor, the combination of a housing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube with rectangular cross-section the fixed Walls of which are formed by said housing, a'varying or moving wall for varying the width of the open- 6.- In a carburetor, the combination of a hous ing through said air metering tube, a fuel orifice in said air metering tube, a fuel reservoir, a fuel passage-connecting said fuel reservoir with said fuel orifice, a fuel metering valve in said fuel pascam-shaped surface on said rotor forming said,

varying wall of said air metering tube, a partition fixed in said housing closing passage at the side of said rotor opposite to the air metering tube and up to the hub of said rotor, an air cushion chamber for said rotor formed in said housing with said rotor forming its piston, a double air seal at the hub of said rotor with the space between the two parts of said air seal subject to the fluctuating pressure of the space between said rotor and the throttle of the carburetor, proportioning means including a connecting rod and levers, interconnecting said rotor and the mov-,

able member of said fuel metering valve so that the fuel metering valve is actuatedv by movements of the rotor, a movable fulcrum for one of the levers which form part of the means by which the movements of the aforesaid rotor are transmitted to the rotatable member of the fuel metering valve, and a means of connection between said fulcrum and, the throttle of the carburetor by which said fulcrum is moved in one direction by opening the throttle and in the opposite direction by closing the throttle, whereby the effective length of said lever is changed and the ratio of the movements of the rotatable member of the fuel metering valve to the movements of the aforesaid rotor is changed, substantially as described.

9. In a carburetor, the combination of a housing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube; a rotor adapted for rotary movement and with a part of its exterior surface forming a portion of the wall-of the metering tube and adapted, upon rotation of thevrotor, to vary the size of the opening through the metering tube, said metering tube having an orifice; a fuel reservoir; a fuel passage connecting said fuel reservoir with said fuel orifice; a fuel metering valve in said fuel passage; a partition, fixed in said housing closing the air passage at the, side of said rotor opposite r to the airmetering tube; an air cushion chamber for said rotor formed in'said housing with said rotor forming its piston, rotatable movement of said rotor being effected and the size of the opening through said metering tube being increased by an increase in the volume of air passing through the carburetor; and means connecting the rotor and said fuel metering valve so that the fuel metering valve is actuated by movement of the rotor.

10. In a carburetor, the combination of a housing having a mixing chamber formed therein, said mixing chamber comprising an air metering tube; a rotor adapted for angular movement and with part of its exterior surface forming a portion of thewall of said air metering tube and adapted, upon angular movement of the rotor, to vary the width of the opening through said air metering tube, angular movement of said rotor being effected and the width of. the opening through said air metering tube being increased by an increase in the volume of air passing through the carburetor; said air metering tube having a fuel orifice; afuel reservoir; a fuel passage connecting said reservoir with said orifice; a fuel metering valve in said fuel passage; a partition fixed in said housing closing the air passage at the side of said rotor opposite the air metering tube, an air cushion chamber for said rotor formed in said housing with said rotor forming its piston; and proportioning means interconnecting said rotor and the movable member of said fuel metering valve so that the fuel metering valve is actuated by movements of the rotor.

REUBEN M. GROSJEAN. 

